1. Field of the Invention
This invention relates to an ink jet recording apparatus for effecting recording on a recording medium by discharging ink through a discharge port and to an ink cartridge for use in the recording apparatus. More particularly, this invention relates to an apparatus having separable units having different functions and independently attached to the apparatus.
For example, the separable units comprise a main body unit, a feed unit, a recording unit and a recovery unit and so on which form, for example, an ink jet apparatus when connected. The separable units also comprise, for example, ink container members which form, for example, an ink cartridge when connected. The apparatus comprises, for example, an ink jet recording apparatus or an ink cartridge.
2. Related Background Art
Conventionally, a type of ink jet recording apparatus for effecting recording by jetting droplets of ink through a nozzle of a recording head according to recording data has a section for transporting a recording medium, a section on which the recording head is mounted, a recovery unit for preventing an ink supply passage and the nozzle from clogging and for recovering each of the passage and the nozzle from a clogged state.
Referring to FIG. 1 which is a schematic perspective view of a conventional ink jet recording apparatus of this type, a transport roller 504 for transporting a recording medium is axially supported through a shaft 3 on chassis 501 and 502 and is driven by a driving source (not shown) through a belt transmission mechanism 505. The recording medium is transported while being guided by a paper pan 506 and a guide plate 507. Recording heads 508 to 511 having a plurality of ink discharge ports are mounted on a carriage 512 which is supported and guided by a pair of guide rails 513 fixed between the chassis 501 and 502 and which is moved for scanning by a driving source (not shown) through a belt 514. An interchangeable ink cartridge 515 is connected to the carriage 512 by a supply pipe 516 to supply ink to the recording heads 508 to 511. A recovery unit 517 has caps 518 to 521 reciprocatively moved by a driving source (not shown), and a pump for producing a pressure by the driving source.
The transport portion, the head mount portion, the recovery unit 517 and so on are integrally assembled on the chassis 501 and 502 and chassis 522 and 523.
This conventional apparatus, however, can be actually used for recording to confirm whether or not the apparatus works correctly only after the overall assembly has been completed. If a malfunction takes place, troublesome operations for dismounting the components for repair of the malfunctioning portion and thereafter reassembling the components are required. It is also required to inspect the reassembled components again. Moreover, once the ink flow into the ink supply passages, it is necessary to employ means for copying with the outflow of the ink during the operation of disconnecting intermediate portions of the passage. This operation is very difficult in respect of maintenance also. It is sometimes necessary to interchange the whole of the recording unit, which is very wasteful.
In the field of electrophotography, U.S. Pat. No. 4,386,838 (patented on Jun. 7, 1983) discloses an arrangement using independently separable units. In this arrangement, each of the units, e.g., a developing device and a cleaning device, is made separable. However, the invention disclosed in that publication relates to the field of electrophotography different from that of ink jet recording and therefore any consideration is paid to use of ink including supply of ink to the recording head.
On the other hand, the construction of a known type of ink cartridge formed by fixing a plurality of ink containers is as described below. An ink jet recording apparatus which effects recording by discharging ink through a discharge port of a recording head according to recording data is provided with an ink cartridge for supplying ink to the recording head. Specifically, for color ink jet recording apparatus, a cartridge having a plurality of ink containers having ink of different colors housed in one casing has been proposed.
FIG. 2 is a partially fragmentary schematic perspective view of a conventional ink cartridge. In FIG. 2 the ink cartridge 531 has a casing 532 in which ink containers 533 in the form of a bladder containing inks of three colors are accommodated. Holes 534 through which the respective color inks are extracted are formed. Needles 537, 538, and 539 positioned to face the ink extraction holes 534 are mounted on joint bases 535 and 536 provided on a recording apparatus (not shown). The needles 537 to 539 communicate with supply pipes 540, 541 and 542 connected to a recording head.
The inks provided in the ink cartridge are thereby supplied from the ink containers 533 to the recording head through the needles 537 to 539 and the supply pipes 540 to 542.
FIG. 3 is a partially exploded perspective view of a cartridge 551, showing the internal construction of this cartridge. Each of ink containers 553 is formed of an ink container bladder 563, an ink extraction hole member 564 and a cap 565. A partition plate 566 has a U-shaped groove 566a corresponding to the shape of the extraction hole members 564. A rib 552a is formed on a casing 552 and a U-shaped groove 552b is formed on the rib 552a.
In this construction, the ink containers 553 are positioned by being pinched at the extraction hole members 564 between the groove 552b of the casing 552, the groove 566a of the partition plate 566 and an unillustrated lid member.
In this conventional type of cartridge, however, there is a possibility of each ink container 553 rotating in the grooves 552b and 566a so that an unnecessary force is applied to the ink container to pressurize the ink. The discharge performance of the recording head is affected by the change in the ink pressure thereby caused, resulting in a deterioration in printing qualities or, in the worst case, occurrence of a leak of the ink. In addition, unless the partition plate 566 is firmly fixed to the casing 552, each ink container 553 can be easily shifted from the correct position. In such an event, it is difficult to correctly insert the needles 557 to 559. There may be also a risk of the partition plate 566 being moved by vibration, resulting in damage of the casing 552.
Problems relating to filling of ink into the ink containers are also encountered as described below.
Ink is injected or filled in one of two different ways. That is, ink having different colors are filled into the ink containers 553 after the ink containers have been set in the casing 552, or the ink is filled after the formation of the ink containers, and the ink containers containing the respective color inks are set in the containers 552.
However, if, in the case of the above-described conventional cartridge, ink is filled after the setting of the cartridge, a leak of the ink which may occur in each ink container 553 cannot be checked easily since the casing 552 is already formed. In a case where the ink is previously filled into the ink containers 553, there is a possibility of failure to set the containers in the proper positions in the casing 552 because the containers are equal in shape, although ink leak checking can be performed easily.